The United States is concerned about the deepening of military cooperation between Russia and North Korea amid the meeting of presidents Vladimir Putin and Kim Jong Un, which took place the day before.

"We haven’t seen the full manifestation of this meeting yet or what the full outcomes of this meeting will be, but when you see the two – when you see Kim Jong-un vowing to provide full, unconditional support for Russia’s so-called "sacred fight" to defend its security interests, which of course is not what it’s doing with respect to the war in Ukraine, that of course is troubling," said Matthew Miller, the Spokesperson for the US Department of State.

A representative of the State Department says that the US has reason to believe that Putin and Kim Jong Un discussed military supplies.

However, he emphasised that the fact that Russia is asking for help from the DPRK shows how the war unleashed against Ukraine is developing for the Kremlin.

"A year and a half ago Vladimir Putin launched this war thinking he was going to restore the glory of the Russian empire, failed in all of his maximalist, imperialist aims, and now a year and a half later, after losing tens of thousands of Russian soldiers and spending billions and billions of dollars, here he is begging Kim Jong Un for help," Miller said.

He added that the US would "without hesitation" introduce sanctions against the Russian Federation and North Korea.

Kim Jong Un and Vladimir Putin met on September 13 at the Vostochny [Eastern] Cosmodrome. On the day of Kim's arrival in the Russian Federation, North Korea launched two ballistic missiles near its eastern coast.

The United States threatened to aggressively apply existing sanctions against Pyongyang and introduce new ones if North Korea provided weapons to Moscow for its war in Ukraine.